/* ValidDHCPOffer():
* Target issued the DISCOVER, the incoming packet is the server's
* OFFER reply. If the offer contains the vendor specific
* VS_PPADHCPSRVR option and the string within that
* option is correct, then accept the offer; by issuing a request.
*/
ValidDHCPOffer(struct dhcphdr *dhdr)
{
uchar *op, *op1;
op = op1 = 0;
op1 = DhcpGetOption(DHCPOPT_VENDORSPECIFICINFO,dhdr+1);
if(op1) {
op = DhcpGetOption(VS_PPADHCPSRVR,op1+2);
}
if(op) {
if(!strncmp(op+2,PPADHCPSRVR_STR,sizeof(PPADHCPSRVR_STR)-1)) {
return(1);
}
}
return(0);
}
/*!
* \brief Send DHCP datagram and wait for a specified answer.
*
* \param slen Length of message to send.
* \param xtype Expected response type.
*
* \return The number of data bytes received, 0 on timeout or -1 in
* case of a failure.
*/
int DhcpTransact(u_short slen, u_char xtype)
{
u_char type;
u_char retry;
int rlen = 0;
for (retry = 0; retry < 3; ) {
/*
* Send a message, if nothing has been received yet.
*/
if (rlen == 0) {
if (UdpOutput(INADDR_BROADCAST, DHCP_SERVERPORT, DHCP_CLIENTPORT, slen) < 0) {
/* Transmit failure, must be a NIC problem. Give up. */
return -1;
}
}
/*
* Do a retry on timouts or failures. A receive failures may be
* caused by a hardware failure or a bad frame.
*/
if ((rlen = UdpInput(DHCP_CLIENTPORT, 5000)) <= 0) {
retry++;
continue;
}
/*
* Check if the response contains the expected ID and
* message type.
*/
if (rframe.u.bootp.bp_xid == sframe.u.bootp.bp_xid &&
DhcpGetOption(DHCPOPT_MSGTYPE, &type, 1) == 1 &&
type == xtype) {
DEBUG("[DHCP]");
break;
}
}
return rlen;
}
/*!
* \brief Query any DHCP server on the local net.
*
* On success, this routine will fill some global
* variables:
*
* - my_ip
* - server_ip
* - bootfile
* - my_netmask
*
* \return 0 on success, -1 otherwise.
*/
int DhcpQuery(void)
{
BOOTPHDR *bp;
u_short slen;
u_char i;
u_long sid;
register u_char *cp;
/*
* Nothing to do if we got a fixed IP address.
*/
if (confnet.cdn_cip_addr) {
confnet.cdn_ip_addr = confnet.cdn_cip_addr;
return 0;
}
confnet.cdn_ip_addr = 0;
/*
* Setup bootp message.
*/
bp = &sframe.u.bootp;
bp->bp_op = 1;
bp->bp_xid = *((u_long *)&confnet.cdn_mac[2]);
bp->bp_htype = 1;
bp->bp_hlen = sizeof(confnet.cdn_mac);
memcpy_(bp->bp_chaddr, confnet.cdn_mac, 6);
/*
* Add DHCP option for discover message.
*/
bp->bp_cookie = 0x63538263;
i = DHCP_DISCOVER;
DhcpSetOption(bp->bp_options, DHCPOPT_MSGTYPE, &i, 1);
/*
* Send DHCP discover and wait for any response.
*/
slen = sizeof(BOOTPHDR) - sizeof(sframe.u.bootp.bp_options) + 4;
if (DhcpTransact(slen, DHCP_OFFER) <= 0) {
return -1;
}
/*
* Get the server ID option.
*/
DhcpGetOption(DHCPOPT_SID, &sid, 4);
/*
* Reuse the bootp structure and add DHCP options for request message.
*/
DEBUGULONG(rframe.u.bootp.bp_yiaddr);
i = DHCP_REQUEST;
cp = DhcpSetOption(bp->bp_options, DHCPOPT_MSGTYPE, &i, 1);
cp = DhcpSetOption(cp, DHCPOPT_REQUESTIP, (u_char *)&rframe.u.bootp.bp_yiaddr, 4);
DhcpSetOption(cp, DHCPOPT_SID, (u_char *)&sid, 4);
/*
* Send DHCP request and wait for ACK.
*/
slen = sizeof(BOOTPHDR) - sizeof(sframe.u.bootp.bp_options) + 16;
if (DhcpTransact(slen, DHCP_ACK) <= 0) {
return -1;
}
/*
* Retrieve local IP, bootp server IP, bootfile name and netmask.
*/
confnet.cdn_ip_addr = rframe.u.bootp.bp_yiaddr;
confboot.cb_tftp_ip = rframe.u.bootp.bp_siaddr;
for (cp = rframe.u.bootp.bp_file, i = 0; *cp && i < sizeof(confboot.cb_image) - 1; cp++, i++) {
confboot.cb_image[i] = *cp;
}
confboot.cb_image[i] = 0;
DhcpGetOption(DHCPOPT_NETMASK, &confnet.cdn_ip_mask, 4);
#if 0
/*
* I'd say that tftpd32 is buggy, because it sends siaddr
* set to zero. This hack will fix it.
*/
if (confboot.cb_tftp_ip == 0)
confboot.cb_tftp_ip = rframe.ip_hdr.ip_src;
#endif
return 0;
}
/* processDHCP():
* Actually this is processBOOTP, but we call it processDHCP here so that
* the same code in enetcore.c can be used to call either function (depending
* on what has been configured into the uMon build).
*/
int
processDHCP(struct ether_header *ehdr,ushort size)
{
char getbootfile = 0;
struct ip *ihdr;
struct Udphdr *uhdr;
struct bootphdr *bhdr;
ulong ip, temp_ip, cookie;
uchar buf[16], bootsrvrip[16], *op;
ihdr = (struct ip *)(ehdr + 1);
uhdr = (struct Udphdr *)((char *)ihdr + IP_HLEN(ihdr));
bhdr = (struct bootphdr *)(uhdr+1);
/* Verify incoming transaction id matches the previous outgoing value: */
if (xidCheck((char *)&bhdr->transaction_id,1) < 0)
return(-1);
/* If bootfile is nonzero, store it into BOOTFILE shell var: */
if (bhdr->bootfile[0])
getbootfile++;
/* Assign IP "server_ip" to the BOOTSRVR shell var (if non-zero): */
memcpy((char *)&temp_ip,(char *)&bhdr->server_ip,4);
if (temp_ip)
getbootfile++;
IpToString(temp_ip,(char *)bootsrvrip);
/* Assign IP address loaded in "your_ip" to the IPADD shell var: */
memcpy((char *)BinIpAddr,(char *)&bhdr->your_ip,4);
memcpy((char *)&temp_ip,(char *)&bhdr->your_ip,4);
printf("IP: %s\n",IpToString(temp_ip,(char *)buf));
/* If STANDARD_MAGIC_COOKIE exists, then process options... */
memcpy((char *)&cookie,(char *)bhdr->vsa,4);
if (cookie == ecl(STANDARD_MAGIC_COOKIE)) {
/* Assign subnet mask option to NETMASK shell var (if found): */
op = DhcpGetOption(DHCPOPT_SUBNETMASK,&bhdr->vsa[4]);
if (op) {
memcpy((char *)BinNetMask,(char *)op+2,4);
memcpy((char *)&ip,(char *)op+2,4);
printf("NETMASK: %s\n",IpToString(ip,(char *)buf));
}
/* Assign first router option to GIPADD shell var (if found): */
/* (the router option can have multiple entries, and they are */
/* supposed to be in order of preference, so use the first one) */
op = DhcpGetOption(DHCPOPT_ROUTER,&bhdr->vsa[4]);
if (op) {
memcpy((char *)BinGipAddr,(char *)op+2,4);
memcpy((char *)&ip,(char *)op+2,4);
printf("GIPADD: %s\n",IpToString(ip,(char *)buf));
}
}
/* Call loadBootFile() which will then kick off a tftp client
* transfer if both BOOTFILE and BOOTSRVR shell variables are
* loaded; otherwise, we are done.
*/
/* If the bootp server gave us the bootfile and boot server IP,
* then call loadBootFile()...
*/
if (getbootfile == 2)
loadBootFile((char *)bhdr->bootfile,(char *)bootsrvrip);
else
DHCPState = BOOTPSTATE_COMPLETE;
return(0);
}
